JPS6353945B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a sheet-fed offset printing machine having at least one printing mechanism for double-sided printing, consisting of three plate cylinder/blanket cylinder pairs, and a chain transport mechanism, comprising: In this printing mechanism, a blanket cylinder that performs back side printing receives a sheet to be printed and guides it along two other blanket cylinders that each perform one front side printing.

Sheet-fed offset printing machines for double-sided printing of this type are covered by Utility Model No. 1 of the Federal Republic of Germany.
1158394, FIG. 2, in which the sheet to be printed is gripped by a gripper device on a blanket cylinder which performs reverse printing; The gripper device guides the sheet to be printed along two further blanket cylinders, each of which carries out one surface printing. The sheet, which has been printed twice on the front side and once on the back side, is then transferred to a take-up cylinder, which guides the sheet into a two-part conveyor chain mechanism, which The sheets are transported to a stack by means of a transport chain mechanism. The use of a take-up cylinder makes this known printing mechanism expensive and bulky. Moreover, the take-up cylinder limits the accessibility of the impression cylinder adjacent to the take-up cylinder and its dampening or inking mechanism.

SUMMARY OF THE INVENTION The object of the invention is to design a sheet-fed offset printing machine according to the general concept of patent claim 1 in a manner that does not require a take-up cylinder.

According to the invention, this problem is solved in that the chain transport mechanism is guided around the blanket cylinder which carries out the second front printing, and after the back printing and the first front printing the sheet is , the sheet is picked up by the gripper of the chain transport mechanism from the blanket cylinder for back side printing, and after the second front side printing has been performed, the sheet is transferred from the printing mechanism by the chain transport mechanism to the paper delivery device. The solution was to ensure that they were removed before they were shipped to the city.

Compared to the known printing mechanisms, the printing mechanism according to the invention has the advantage that it is cheaper to manufacture, has a shorter sheet transport path, and is more accessible to the cylinder of the printing mechanism in the delivery area. There is.

Next, the configuration of the present invention will be specifically explained with reference to the embodiments shown in the drawings.

The sheet-fed printing press shown diagrammatically in FIG. 1 has a printing mechanism 1 in which three plate/blanket cylinder pairs are provided. The sheets fed to the printing mechanism 1 via a conventional mechanism (not shown), for example a gripper device, are gripped by a blanket cylinder 3, which communicates with the forme cylinder 2. When passing between the printing form cylinder 4 and the blanket cylinder 5 which communicates with it, the lower side of the sheet is printed on the reverse side by the blanket cylinder 3, and the upper side is printed on the front side by the blanket cylinder 5. This sheet is then fed in the printing unit 1 by means of a blanket cylinder 3 to a further blanket cylinder 7 which likewise cooperates with a form cylinder 6 .

According to the invention, a chain transport mechanism 9 is guided around the blanket cylinder 7, which performs the second surface printing on the upper side of the sheet. The sheets printed in the printing mechanism 1 and previously fed from the paper feed device 8 are gripped by grippers arranged in the chain in a conventional manner and conveyed to the paper delivery device 10 . After the sheet has finished the first double-sided printing,
It is gripped by the grippers 15 of the chain transport mechanism 9. The gripper 15 guides the sheet by partially winding it around the blanket cylinder 7;
and 7, a second surface printing is carried out by the blanket cylinder 7, and then the printed sheet is transferred to the printing mechanism 1.
It is discharged outside.

Due to the advantageous guidance of the chain transport mechanism 9, the sheets are guided in the shortest path to the delivery device 10, without the need for a take-up cylinder. The blanket cylinder 3 or a gripper mounted in a conventional manner in a hole in this blanket cylinder 3 can grip the sheet, advantageously without a feed cylinder being placed in front of it, so that it is possible to grip the sheet without placing a feed cylinder in front of it. It is advantageous to arrange a pneumatic device 11.
The suction flow of this air device prevents the sheets to be fed into early contact with the surface of the blanket cylinder 3, which is to be printed on the back side. Instead of such a pneumatic device 11, an electrostatic charge device (not shown) may be used. By means of this electrostatic charging device, the sheet is drawn to the surface of the blanket cylinder 3 as soon as it is received by the blanket cylinder 3, so that the sheet is not displaced during the subsequent printing process.

FIG. 2 shows an advantageous embodiment of the invention, in which printing mechanism 1 is connected to the rear of printing mechanism 13 of the same type. In principle, the structure of the printing mechanism 13 is the same as that of the printing mechanism 1, so that the same reference numerals are used for the same structural units.

In the embodiment shown in FIG.
In the embodiment according to FIG. 2, the chain transport mechanism 9, which guides the printed sheets and discharges the printed sheets from the printing mechanism 1, has a drum 12 which is additionally arranged in front of the blanket cylinder 3 of the printing mechanism 13. They are surrounded and guided. Thereby, the sheets printed by the printing mechanism 1 can be delivered to the first cylinder of the printing mechanism 13 with correct orientation.

The sheets are of the same type as the printing mechanism 1, and the printing mechanism 13
However, two further front-side printings and one back-side printing are carried out, and then the sheet is moved, according to the invention, also in the printing mechanism 13 to the blanket cylinder 7, where a second front-side printing is carried out. It is transported to the delivery device 10 by a chain transport mechanism 14 that is guided around it.

Since each cylinder in the printing mechanism 1 can be cut off according to each request, the following printing is possible.

1/0 2/0 1/1 2/1 0/1 By increasing the number of printing mechanisms, the print variation can be correspondingly increased.

In this case, the first number is the number of times the front side is printed, and the number to the right of the diagonal line is the number of times the back side is printed.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a sheet-fed offset printing machine with one printing mechanism for two front side printings and one back side printing; FIG. 1 is a schematic illustration of a sheet-fed offset printing press with two printing mechanisms in each case; FIG. 1... Printing mechanism, 2... Plate cylinder, 3... Rubber cylinder,
4...Print cylinder, 5...Rubber cylinder, 6...Print cylinder, 7...
Rubber cylinder, 8... Paper feeding device, 9... Chain conveyance system, 10... Paper discharge device, 11... Air device,
12...Drum, 13...Printing mechanism, 14...Chain transport mechanism, 15...Gripper, 16...
Hole.

Claims (1)

[Scope of Claims] 1. A sheet-fed offset printing machine having at least one printing mechanism 1 for double-sided printing, consisting of three plate cylinder/blanket cylinder pairs, and a chain transport mechanism 9, which The blanket cylinder 3 that performs reverse side printing within the mechanism 1 receives the sheet to be printed, and
In the type in which the rubber cylinder is guided along two other blanket cylinders 5 and 7, each of which performs one surface printing,
The chain transport mechanism 9 is guided around the blanket cylinder 7 which carries out the second front side printing, and after the back side printing and the first front side printing the sheet is transferred to the chain conveyor mechanism 9. The gripper 15 picks up the sheet from the blanket cylinder 3 on which back side printing is to be performed, and after the second front side printing is performed, the sheet is transferred to the printing mechanism 1 by the chain conveyance mechanism 9.
1. A sheet-fed offset printing machine having at least one printing mechanism for double-sided printing, characterized in that the sheets are delivered from a sheet-fed sheet to a delivery device 10. 2. Two identical printing mechanisms 1, 13 for double-sided printing, each consisting of three plate/blanket cylinder pairs.
2. A sheet-fed offset printing machine as claimed in claim 1, wherein the printing presses are arranged one after the other. 3 The sheet to be printed is transported to the delivery device 10 by a chain transport mechanism guided around the blanket cylinder 7 of the last printing mechanism which performs the second back printing. A sheet-fed offset printing machine according to claim 1. 4 The plate cylinder 2 assigned to the blanket cylinder 3 that performs reverse printing is located below the paper feeder 8, and the second
A plate cylinder 6 attached to a blanket cylinder 7 that performs surface printing of
is arranged above the chain transport mechanism 9,
The plate cylinder 4 assigned to the blanket cylinder 5 that performs the first surface printing is arranged above the plate cylinder 6 that is assigned to the blanket cylinder 7 that performs the second surface printing. A sheet-fed offset printing machine according to item 1.